U.S. patent number 5,655,975 [Application Number 08/551,989] was granted by the patent office on 1997-08-12 for golf club having vibration damping device and method for making same.
This patent grant is currently assigned to Roush Anatrol, Inc.. Invention is credited to Ahid D. Nashif.
United States Patent |
5,655,975 |
Nashif |
August 12, 1997 |
**Please see images for:
( Certificate of Correction ) ** |
Golf club having vibration damping device and method for making
same
Abstract
A golf club having a vibration damping device including a club
head, a shaft connected to the club head having resonant
frequencies over a predetermined range and a rod disposed within
the shaft with a viscoelastic material interposed between the shaft
and the rod. The rod is flexible and has resonant frequencies over
the same frequency range as the shaft such that the shaft and rod
vibrate out of phase with respect to each other and thereby deform
the viscoelastic material to damp vibrations in the shaft.
Inventors: |
Nashif; Ahid D. (Cincinnati,
OH) |
Assignee: |
Roush Anatrol, Inc. (Sunnyvale,
CA)
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Family
ID: |
27047999 |
Appl.
No.: |
08/551,989 |
Filed: |
November 2, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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484450 |
Jun 7, 1995 |
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Current U.S.
Class: |
473/316; 473/318;
428/36.9; 273/DIG.8 |
Current CPC
Class: |
A63B
60/54 (20151001); A63B 53/00 (20130101); A63B
60/00 (20151001); A63B 60/08 (20151001); A63B
2209/00 (20130101); Y10T 428/139 (20150115); A63B
60/10 (20151001); A63B 53/10 (20130101); Y10S
273/08 (20130101); A63B 60/06 (20151001) |
Current International
Class: |
A63B
53/00 (20060101); A63B 59/00 (20060101); A63B
53/10 (20060101); A63B 053/10 () |
Field of
Search: |
;473/316,317,318,319,320,321,322,323
;273/DIG.23,DIG.3,DIG.8,DIG.22,73F,75,72A,67R,67A ;156/187,145
;428/364,375,36.9 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2575393 |
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Jul 1986 |
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FR |
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2-31770 |
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1990 |
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JP |
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6339551 |
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Dec 1994 |
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JP |
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13337 |
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Jun 1912 |
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GB |
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499155 |
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Jan 1939 |
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GB |
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2053698 |
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Feb 1981 |
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GB |
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2053004 |
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Feb 1981 |
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GB |
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2146906 |
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May 1985 |
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GB |
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2226380 |
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Jun 1990 |
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GB |
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2227418 |
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Aug 1990 |
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GB |
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2259861 |
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Mar 1993 |
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GB |
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Other References
Publication: "Good Vibrations", Golf Digest, Mar. 1995, pp.
70-72..
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Primary Examiner: Passaniti; Sebastiano
Attorney, Agent or Firm: Bliss McGlynn, P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION(S)
The present application is a continuation-in-part of U.S. Ser. No.
08/484,450, filed Jun. 7, 1995.
Claims
What is claimed is:
1. A golf club having a vibration damping device comprising:
a club head;
a shaft connected to said club head having resonant frequencies
over a predetermined range; and
a hollow rod disposed within and detached from said shaft and a
viscoelastic material interposed between said shaft and said rod
and being spiral-wrapped around said rod, said rod and said
viscoelastic material extending a predetermined distance along a
length of said shaft and being separate from said club head, said
rod being flexible and having resonant frequencies over the same
frequency range as said shaft such that said shaft and rod vibrate
out of phase with respect to each other and deform said
viscoelastic material to damp viscoelasticly vibrations in said
shaft.
2. A golf club as set forth in claim 1 wherein said shaft has a
predetermined length, said rod and said viscoelastic material
extending a predetermined distance and centered near a mid-point of
said predetermined length of said shaft.
3. A golf club as set forth in claim 1 wherein said viscoelastic
material is spiral wrapped around said rod.
4. A golf club as set forth in claim 1 further including an
adhesive layer interposed between said viscoelastic material and
said shaft to bond said viscoelastic material to said shaft.
5. A golf club as set forth in claim 4 wherein said adhesive layer
is a polymer-based pressure sensitive adhesive.
6. A golf club as set forth in claim 5 wherein said polymer-based
pressure sensitive adhesive is an acrylic-based, water or solvant
soluble, pressure sensitive adhesive.
7. A golf club as set forth in claim 1 wherein said rod is made of
plastic tubing.
8. A golf club as set forth in claim 1 wherein said viscoelastic
material is made of a soft foam material.
9. A golf club having a vibration damping device comprising:
a club head;
a grip;
a shaft extending between said club head and said grip and having
resonant frequencies over a predetermined range;
a hollow rod disposed within and detached from said shaft;
a viscoelastic material spiral-wrapped around said rod;
an adhesive layer disposed between said viscoelastic material and
said shaft to bond said viscoelastic material to said shaft;
and
said shaft having a predetermined length, said rod being flexible
and having resonant frequencies over the same frequency range as
said shaft, said rod and viscoelastic material extending a
predetermined distance and centered near a mid-point of said
predetermined length of said shaft and being separate from said
club head and corresponding to the frequency range of vibrations to
be damped such that said shaft and rod vibrate out of phase with
respect to each other and deform said viscoelastic material to damp
viscoelasticly multiple frequencies of vibrations over a
predetermined range.
10. A golf club as set forth in claim 9 wherein said rod is made of
plastic tubing.
11. A golf club as set forth in claim 9 wherein said viscoelastic
material is made of a soft foam material.
12. A golf club as set forth in claim 9 wherein said adhesive layer
is a polymer-based pressure sensitive adhesive.
13. A golf club as set forth in claim 12 wherein said polymer-based
pressure sensitive adhesive is an acrylic-based, water or solvant
soluble, pressure sensitive adhesive.
14. A method of making a golf club having a vibration damping
device comprising the steps of:
disposing a viscoelastic material about a flexible rod;
disposing an adhesive about the viscoelastic material;
inserting the flexible rod, viscoelastic material and adhesive into
a shaft of the golf club; and
disposing the adhesive against an inner surface of the shaft and
bonding the viscoelastic material to the shaft.
15. A method as set forth in claim 14 including the step of melting
the adhesive to bond the viscoelastic material to the shaft.
16. A method as set forth in claim 14 wherein said step of
disposing a viscoelastic material about a flexible rod comprises
spiral wrapping a viscoelastic material about a flexible rod.
17. A method as set forth in claim 14 including the steps of
wrapping the adhesive about the viscoelastic material and heating
the shaft to a predetermined temperature such that the viscoelastic
material expands and the adhesive is disposed against the inner
surface of the shaft and melted to bond the viscoelastic material
to the shaft.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a golf club having a
vibration damping device and method for making same and, more
specifically, to a light weight golf club having a flexible
vibration damping device incorporated therein and a method for
making same which damps vibrations over a broad range of
frequencies.
2. Description of the Related Art
In the game of golf, a club is used to strike a stationary ball,
driving it along a course with the object of placing the ball in a
hole in the shortest number of strokes. Golf clubs come in a number
of varieties, most prominently distinguished by the shape of the
head. A shaft is attached at one end to the head and typically
includes a grip at the opposite end of the shaft. Club heads may be
generally categorized as "woods," "irons," and "putters" as is
commonly known in the art. The impact of the ball on the hitting
surface or face of the club generates vibratory phenomena on the
shaft of the club. When the ball is hit perfectly, this vibratory
phenomena is not objectionable to the player and may even be
pleasant, creating a distinctive sound indicating that the ball was
well struck in the "sweet spot" of the club face.
On the other hand, when the ball is not hit perfectly at dead
center of the "sweet spot" on the club face, torsional and bending
forces are introduced to the club. These forces result in
unfavorable vibratory phenomena having multiple resonant
frequencies to 5,000 Hz and sometimes higher. These vibrations are
transmitted to the golfer through his/her hands and can be very
unpleasant. Such unpleasant experiences can have a negative effect
on the players and thereby decrease the enjoyment of the game of
golf.
There have been numerous attempts to address and reduce the above
problem. For example, one attempt to address the above problem has
been to provide vibration damping devices which are designed to
specific type of modes of vibration over a limited frequency range.
Such vibration damping devices rely on the constrained layer
damping principle wherein a viscoelastic material is disposed
between a stiff, rigid plate or member and the shaft to be damped.
Vibrations cause the stiff, rigid plate or member to move relative
to the shaft which causes shear in the viscoelastic material.
However, such devices suffer from the disadvantage that they are
limited to damping only those modes of vibration which have their
high modal strain energies at the location of the device and are
not suitable for reducing unwanted vibration over wide frequency
ranges such as encountered by the ball impact on the golf club.
Also, such devices are limited in their application to golf clubs
due to the added weight of the rigid member. More specifically, the
number of modes of the vibration generated in the golf club is a
function of the length of the shaft, among other things. In order
to damp most of the undesirable modes that may be created in a golf
club, the rigid member must be employed over a substantial portion
of the length of the shaft which is unacceptable due to the weight
added to the club shaft by the use of the rigid member. Thus, there
is a need in the art for a vibration damping device which is light
weight, inexpensive and yet can damp resonant vibrations over wide
frequency ranges.
SUMMARY OF THE INVENTION
It is, therefore, one object of the present invention to provide a
golf club having a vibration damping device.
To achieve the foregoing object, the present invention is a golf
club including a club head and a shaft connected to the club head
having resonant frequencies over a predetermined range. The golf
club also includes a rod disposed within the shaft and a
viscoelastic material interposed between the shaft and the rod. The
rod is flexible and has resonant frequencies over the same
frequency range as the shaft such that the shaft and rod vibrate
out of phase with respect to each other and deform the viscoelastic
material to damp vibrations in the shaft.
In addition, the present invention is also a method of making a
golf club having a vibration damping device including the steps of
disposing a viscoelastic material about a flexible rod, wrapping an
adhesive layer around the viscoelastic material and inserting the
flexible rod, viscoelastic material and adhesive layer into a
hollow club shaft. The method also includes the steps of expanding
the viscoelastic material such that the adhesive layer is disposed
against an inner surface to bond the viscoelastic material to the
shaft.
One advantage of the present invention is that a golf club is
provided having a vibration damping device. Another advantage of
the present invention is that the vibration damping device reduces
the unwanted vibration over multiple frequencies of the golf club.
Yet another advantage of the present invention is that a method is
provided for making a golf club having a vibration damping
device.
Other objects, features and advantages of the present invention
will be readily appreciated as the same becomes better understood
after reading the subsequent description when considered in
connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a golf club having a vibration
damping device according to the present invention.
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.
FIG. 3 is a partial fragmentary perspective view of a portion of
the golf club having the vibration damping device of FIG. 1.
FIG. 4 is a schematic fragmentary view of the golf club having the
vibration damping device of FIG. 1 and illustrating a flexible rod
of the vibration damping device out of phase with a shaft of the
golf club to damp vibrations therein.
FIG. 5 is a graph of compliance versus frequency for a shaft of a
golf club without the vibration damping device of FIG. 1.
FIG. 6 is a graph of compliance versus frequency for a flexible rod
of the golf club having the vibration damping device of FIG. 1.
FIG. 7 is a graph of inertance versus frequency for the golf club
having the vibration damping device of FIG. 1.
FIG. 8 is a graph of compliance versus frequency for the golf club
having the vibration damping device of FIG. 1.
FIG. 9 is a partial fragmentary perspective view of a portion of
another golf club having a vibration damping device according to
the present invention.
FIG. 10 is a sectional view taken along line 10--10 of FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
Referring to FIG. 1, one embodiment of a golf club having a
vibration damping device, according to the present invention, is
generally shown at 10. The golf club 10 includes a golf head 12
having a club face 14 which is used to strike a stationary golf
ball in the game of golf. While the club head 12 illustrated in
FIG. 1 is of the type known as a "wood", it should be appreciated
that the golf club could also be of any type of club, such as a
"iron" or a "putter".
The golf club 10 also includes a shaft 16 connected to the club
head 12 and having a predetermined length and resonant frequencies
over a predetermined range. The shaft 16 is hollow and may be
manufactured from a variety of materials commonly known in the art.
The shaft 16 has a grip 18 at its end opposite the club head 12
which is grasped by the golfer during play. It should be
appreciated that the shaft 16 is a one-piece tubular member.
Referring to FIGS. 2 through 4, a rod 20 is disposed within the
shaft 16 and a viscoelastic material 22 is interposed between the
shaft 16 and the rod 20. The rod 20 is a hollow, flexible, thin
walled tubular member disposed substantially concentrically with
respect to the shaft 16. The rod 20 is flexible and tuned to have
resonant frequencies over the same frequency range as the shaft 16
(see FIGS. 5 and 6) such that the shaft 16 and rod 20 vibrate out
of phase with respect to each other and deform the viscoelastic
material 22.
The rod 20 has a modulus of elasticity between 10.sup.5 to 10.sup.7
psi with a wall thickness of between 0.01 and 0.05 inches.
Preferably, the rod 20 is made of plastic tubing for its low weight
properties, but its modulus, thickness, and length are chosen in
such a way to have its resonances occur over the same frequency
range as those of the shaft 16. The viscoelastic material 22 is
preferably made of a high damping foam material or other suitable
high damping material with rubber like behavior. It should be
appreciated that any suitable low modulus and low density
viscoelastic material may be used which has good damping behavior
over the temperature and frequency ranges of operation.
As illustrated in FIGS. 7 and 8, the effect of the vibration
damping device in reducing the response of the golf club 10 in both
free and hand-held conditions are shown over a wide frequency
range. FIG. 7 shows an untreated or baseline shaft and a treated
shaft having a vibration damping device within the shaft 16 in a
free-free configuration. The inertance (g/lb) is less for the
treated shaft then the baseline shaft over a wide frequency (Hz)
range. FIG. 8 shows a hand-held configuration. The compliance
(in/lb) is less for the treated shaft than the baseline shaft over
a wide frequency (Hz) range.
The rod 20 and the viscoelastic material 22 extend a predetermined
distance along the length of the shaft 16 corresponding to the
frequency range of vibrations to be damped such that multiple
frequencies may be damped over a predetermined range. The golf club
10 further includes an adhesive layer 24 interposed between the
viscoelastic material 22 and the shaft 16 to bond the viscoelastic
material 22 to the shaft 16. In one embodiment, the adhesive layer
24 is a sheet of adhesive wrapped about the viscoelastic material
22 and, more specifically, is a shrink wrap adhesive sheet which is
wrapped about the viscoelastic material 22 for bonding it to the
shaft 16.
Additionally, a method, according to the present invention, of
making the golf club 10 having the vibration damping device is
provided. The method includes the steps of disposing the
viscoelastic material 22 about an outer surface of the rod 20 such
that the rod 20 and the viscoelastic material 22 form a diameter
greater than an inner diameter of the shaft 16 of the golf club 10.
The method further includes the step of wrapping the adhesive layer
24 around the viscoelastic material 22 such that the diameter of
the rod 20, viscoelastic material 22 and adhesive layer 24 is
smaller than the inner diameter of the shaft 16 of the golf club
10. The method also includes the steps of inserting the rod 20 and
the viscoelastic material 22 and the adhesive layer 24 into the
shaft 16 and expanding the viscoelastic material 22 such that the
adhesive layer 24 is disposed against the inner diameter of the
shaft 16 to bond the viscoelastic material 22 to the shaft 16.
The step of bonding the viscoelastic material 22 to the shaft 16
also includes the step of melting the adhesive layer 24 to bond the
viscoelastic material 22 to the shaft 16. More specifically, the
step of expanding the viscoelastic material 22 and melting the
adhesive layer 24 include the steps of heating the shaft 16 to a
predetermined temperature such that the viscoelastic material 22
expands and the adhesive layer 24 is pressed against the inside
surface of the shaft 16 and thereby melted to bond the viscoelastic
material 22 to the shaft 16.
An alternative method of bonding the viscoelastic material 22 to
the inside surface of the shaft 16 is to apply a liquid base
adhesive (such as water base adhesive) to the viscoelastic material
22 and slide the vibration damping device inside the shaft 16
before the liquid base adhesive has cured. Time and/or temperature
will cause the liquid to evaporate and the adhesive to cure in
place and bond the device inside the shaft 16.
Referring to FIGS. 9 and 10, another embodiment of a golf club
having a vibration damping device, according to the present
invention, is generally shown at 110. Like parts of the golf club
10 have like reference numerals increased by one hundred (100). The
golf club 110 has the viscoelastic material 122 spiral wrapped
around the rod 120. The rod 120 is a hollow, flexible thin wall
tubular member made of hollow plastic tubing. The viscoelastic
material 122 is a soft foam material which possess high damping
properties. The width, thickness and number of wraps of the
viscoelastic material 122 is selected based on the length,
thickness and diameter of the rod 120. It should be appreciated
that a space 123 exists axially between wraps of the viscoelastic
material 122 about the rod 120.
In operation, the rod 120 and viscoelastic material 122 extend a
predetermined distance and are located or centered near a mid-point
of the shaft 116. As the numerous bending modes of the shaft 116
are excited due to a typical ball impact, the shaft 116 deforms. As
the shaft 116 deforms, it causes the rod 120 to deform, which in
turn, deforms the viscoelastic material 122 and dissipates
vibrational energy in the form of heat in the viscoelastic material
122. The golf club 110 further includes an adhesive layer 124
disposed between the viscoelastic material 122 and the shaft 116 to
bond the viscoelastic 122 to the shaft 116. In one embodiment, the
adhesive layer 124 is a polymer-based pressure sensitive adhesive
such as an acrylic-based, water or solvent soluble, pressure
sensitive adhesive.
The present invention has been described in an illustrative manner.
It is to be understood that the terminology which has been used is
intended to be in the nature of words of description rather than of
limitation.
Many modifications and variations of the present invention are
possible in light of the above teachings. Therefore, within the
scope of the appended claims, the present invention may be
practiced otherwise than as specifically described.
* * * * *